Fuel enriching means



Aug. 22, 1933. c. F. JOHNSON 3,923,86

FUEL ENRICHING MEANS Filed Mar-Ch 21, 195o IIIIIIIIIIIIIIIIIII f, Il

Patented Aug. 22, 1933 PATENT OFFICE UNITED STATES FUEL ENRICHING MEANS Chester F. Johnson, Detroit, Mich.

Application March 21, 1930. Serial No. 437,666 Claims. (Cl. 12S-119) vention a body has a mixture outlet passage "4 conditions. It is accordingly an object of this invention to provide an improved and simplified priming device cooperating with and supplementing the action of the normal choking control and under the same control so that'the action thereof can be available as desired.

It is another object of this invention to provide a carbureter having a priming device delivering fuel above the throttle, the priming device having a normally open air bleed serving as an economizer under operating conditions and at the same time nullifying the effect of suction on the priming device, the closing of the air bleed imposing manifold suction on the priming device and thus causing the delivery of fuel therefrom.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawing.

This invention (in a preferred form) is illustrated in the drawing and hereinafter more fully described.

On the drawing:

Figure 1 is an elevation of a carbureter incorporating a priming device embodyingrthe features of this invention.

Figure 2 is a fragmentary section on II-II of Figure 1. s.

Figure 3 is a fragmentary detail section on the line III-III of Figure 1.

As shown on the drawing:

An air valve type of carbureter has been chosen to illustrate a specic embodiment of this invention although it is to be understood that this invention is equally applicable to other types of carbureters, one phase of the invention comprising a cooperative action between the priming system and the carbureter choke valve.

In the air valve carburetor illustrating this inthe line charge facilitates starting under unfavorable- 11 controlled by a throttle valve on a shaft 12, a iioat bowl 13 therebelow supplying fuel to a primary mixing system, not shown, to which secondary air is added from a iiap air valve 6 14 backed by a spring 15 between two seats- 16 and 17. The lower seat 17 is movable and has aV downwardly extending stem 18 engaged by an arm 19 associated with a choke control lever 20.

When the choke control lever is moved nearly 6 toits dotted line position in Figure 1 the lower 1 spring seat 17 is lifted to compress the spring 15 to hold the air valve closed, VThe foregoing structure is in effect a combined air valve and a choke` valve since holding the valve 14 closed vagainst increased suction gives the .same result as closing a butterfly choke valve in the airy vintake to a carburetor.

rIn the carburetorchosen for illustrative purposes an air pump, indicated as a whole by the 7 reference numeral 21, is interconnected with the i 5- throttle and acts to increase the air pressure above the fuel in the float bowl when the throttle is opened suddenly. This particular accelerating arrangement requires a slightmodification of the priming device hereinafter to be described,

which modification would' not be necessary if the air pressure above the fuel were notA increased to cause 'the VVtemporary delivery ofY a supplemental fuel charge through the Vnormal.8 nozzle system. Anair bleed passage 22 opens into the mixture passage 11 above the throttle therein and normally receives its air supply through a larger vertical passage' 23 open at its lower end. The

rupper end of a priming tube 24 is centered in and in spaced relationship to the passage 23 and a collar 25, sliding on the tube 24, serves as an air bleed valve to close the lower end of the passage 23, cutting off the inflow of air and thus imposing manifold suction on the priming tube.

The lower end of the tube 24 is threaded into a passage 26 in the float bowl body, whichv passage 26 is in communication with the fuel in l the oat bowl through a restricted orifice 27. e Thus when the collar 25 cuts oif the air bleed the manifold suction draws fuel from the float bowl through the orifice 27, passage 26 and tube` ,l

24 delivering the priming fuel into the manifold l including the orifice 27, so that the capacity of air valve held 'closed to actas a choke.

the tube 24 and passage 26 must be proportioned to the delivery through the orice 27 due to the operation of the accelerating pump in order to prevent the pump from ejecting fuel from the top of the tube 24. The restricted inlet orifice 27 thus prevents such overflow while supplying sumcient fuel for priming purposes due to the high manifold suction created by starting with the choke closed.

The collarv or valve 25 is arranged to belifted into closing engagement in the passage 23 by the last part of the closing movement of the choke operating lever 20 corresponding to the all out position in the case of the usual pull type of dash control. To accomplish` this result an arm 28 is formed on the lever 20 and engages beneath an offset spring seat 29a formed on a lever 29 pivoted on the choke control shaft 30 carrying the arm 19 and lever 20. The outer end of the lever 29 is linked to the collar 25 by arod 31. The 'lever 29 is normallyhe-ld in its lower full line position by a spring 32 and is only moved upwardly when lthe choke lever arm 28 approaches the limit of its motion and makes contact with the spring seat on the lever thus lifting the collar 25. With this arrangement the priming device of' this invention is brought into action after the choke is fully effective and the operation thereof is optional with'the operator. v,In starting an engine under moderately cold conditions it may only be necessary to partially pull out the choke control to increase the resistance to opening of the air valve which increased resistance to opening increases the fuel delivered throughl the normal fuel system, the priming device remaining inoperative. Under 'severe conditions the very last part of the chokercontrol movement operates through .the lever 29 and-rod 31 to lift the collar or valve 25 and thus puts the fuel chamber in direct cornmunication the mixture passage above the throttle, the suction at this point being very high when the 'motor is cranked over with the This high suction induces a flow of fuel from the ,float chamber through the tube 2e and passage 22, which fuel, when added to that produced by the choking arrangements, produces a very rich mixture, a part of which -is delivered Well above the throttle and thereby insures a very prompt starting of the engine.

t will thus be seen that I have provided an improved and simplin'ed priming device which comes into action after 'the usual choke is in full operation and has been found insufficient as in severely cold weather. k

I am aware that many changes may be made and numerous details lof construction may be varied through a wide range without departing from the principles ofY this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise `then necessitated by the prior'art. Y

I claimas follows: Y

1. In a carbureter including a fuel chamber,

'ing means for closing said air bleedV during the f' a mixture outlet containing a throttle valve and a choke controlled air supply, a priming passage leading from below the iluid level in said fuel chamber to the mixture outlet above the throttle therein, means comprising an air bleed into said priming passage to normally render the same inoperative, and means for closing said air bleed to subject the priming passage to 'the suction in the mixture outlet above the throttle therein. g5

2. In a carbureter including a fuel chamber', a mixture outlet containing a throttle valve and a choke controlled air supply, a priming passage leading from below the fluid level in said fuel chamber to the mixture outlet above the throttle therein, means comprising an air bleed into said priming passage to normally render the same inoperative, means for closing said air bleed to subject the priming passage to the suction in the mixture outlet above the throttle therein, Vand means associated with the choke for operating the choke and also the meansY for elo. the airV bleed during the last part of Ythe 'movement of the choke control.

bleed opening into said priming passage and adapted when open to prevent the action of suction on the fuel in said float chamber, and means for closing said air bleed Vto cause the priming passage to deliver .iuel from said float chamber to the mixture outlet passage.

4. A earbureter including a fuel chamber and a mixture outlet passage, a v priming passage connecting the mixture outlet pas c ve to Vthe fuel chamber beneath the level ofthe iuel there in whereby suction at the mixture outlet is adapted to draw fuel through the priming sage, an air bleed into said priming passage, choking means for the carbureter adapted to increase the suction in said mixture outlet passage, and means associated with the choking Vclicking means for the carbrreter adapted to increase the suction in said ixture outlet sage, and means inY cooperation with said chosn last partof the closing movement of said ing` means to cause the priming passage to deliver fuel from said fuel chamber.

CHESTER F. JOHNSON. 

